Space telegraphy.



J. S. STONE.

SPACE TELEGRAPHY.

APPLICATION HLED DB0.14,1905,

9E, 6,895 Patented Mar. 30, 1909.

BBHEETB-SQEEET 1.

Patented Mar. 3o, 19,09'.`

` 3 SHEETS-SHEET 2 J. S. STONE. SPACE TBLEGBAPHY. APPLICATION HLBD DBG.14,1905.

@l 6.895. Patented Mar. 30, 1909. 3 SHEETS-SHEET 3.

(//l/ (2 iig E T y; www...

.UMTED sfraras Parisi i JOHN STONE STONE, OF CAMBRIDGE, MASSACHUSETTS, ASS-IGNOR TO STONE TELEGRAPH` ANDTELEPHONE COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION. OF MAINE,

SPACE TELEGRAPHY. n

vSpecication of Letters Patent.

Patented March 30, 1909.

Application led December 14, 1905.- Serial No. 291,702.

and useful Improvement in Space Telegrapliy, of which the following is a specification.

mitting intelligence from one station to another by means of electromagnetic waves without the use of wires to `guide the waves to their destina-tion; and it relates more particularly' to systems for receiving signals transmitted by such waves.

In the artof wireless telegraphy noproblem is ofgreate'r importance from an industrial and commercial standpoint than that of rendering the receiving instruments ofl wireless telegraph stations immune from interference. There are two principal kinds of` interference: First, that which arises from such stray electromagnetic waves as are produced by lightning, by, .magnetic storms, by sparks in neighboring circuits, such for instance as occur in trolley circuits, and also fromelectromagnetic waves emanating from wireless telegraph stations other than that with'which communication is desired; and second, that which arises from electrical charges which accumulate upon the vertical oscillator or elevated receiving conductor under various conditions of weather, provided said elevated conductor has no adequate electrical connection to the earth.

In my prior LettersITatent Nos. 7 G7 ,994, 714,756 andv other Letters Patent, I have disclosed means for rendering the receiving instruments immune from interference of the first class. above mentioned, namely, interference 'which arises from electromagnetic waves emanating from foreign stations, and which arises from'abrupt or impulsive electrical forces; and the yobject of myprese'nt inventior'i` is to provide a wireless telegraph receiving system, the instruments of which shall be immunefrom interference of the second class, namely, static interference.

-The greatest security from static interference' is obtained by providing theelevated` receiving conductor with an adequate conductive connection to earth and by placing the receiving device in a local circuit made resonant by a coil and a condenser to the fre- My invention 'relates to the art of trans-4 quency of the electrical oscillations to which the receiver is intended to respond,A` as shown in my aboye mentioned Letters Patent. However, in some instances it is advisable to- 'include a condenser or condensers in the elevated conductor as more fully explained in connection with some of the figures of my Letters Patent No. 7 67 ,994, and 1n` connection with my Letters Patent Nos. 767 ,990,

802,425' and other Letters Patent. y

By the means set forth in the present application static interference is readily overcome even ywhena condenserl is serially in, cluded in the elevated conductor, for by said means said conductor may, always be given a metallic connection to the earth sufficient to maintain it clear of static charges With-- out in any appreciable degreev interfering with its operation as a receiving conductor; and it is readily overcome even if the oscillation vdetector is included directly in said receiving conductor. I

I accomplish the hereinbefore stated objects of my invention by connecting across the terminals of a' condenser serially included in the elevated conductor, or across the terminals of an oscillation responder similarly included in said conductor, or across the terminals of that portion of the conductor which iiludes said condenser and,

responder, a device having, -for the f frequency of the waves to bel received, an impedance greater than the impedance of said condenser, said responder, or both.

My invention may best be understood by I having reference to the drawings which accompanyand form a part of this specification and which illustrate diagrammatically several forms'ofl apparatus and circuit arrangements whereby the hereinbefore stated objects maybe carried into effect.

-In the drawings, Figure l represents a space telegraph receiving system in which the oscillation responder is serially included in `the elevated conductor; Fig..2 represents a space telegraph receiving system in which theos'cillation responder and a condenser are serially included in the elevated conductor; Fig.v 3 represents another type fof space telegraph system; and Figs. 4g, 5 and 6 represent space telegraph systems embddying elevated conductor systems of the type set 'forth in my Letters Patent No. 802,425.

In the figures, A is asource'of varying.

.current generator. -n

'M M M M" are transformers.

I1 Ilfand I 1 are transformer primaries, and I, I2 I2 are transformer sec.

ondaries which preferably are so related to their respective primaries as to produce transformers of large magnetic leakage.

C C1 C', C. C" C2 C3 C4 C5 and C6 are condensers. P 1) are oscillation detectors able type.

B B are batteries. L is a protective inductance. L1 L, are tuning inductances. I V is an elevated conductor consisting of a plurality of wires, of which the wires o v are employed for receiving.

' K is a key.

of any suit- R is a resistance which with the battery B constitutes a potentiometer.

T 'I" are signal-indicating devices.

In Fig. 1 1 have shown a simple wireless telegraph receiving system of the kind first employed in this art in which kthe oscillation detector IW. is included in the elevated conductor. Connected across the terminals ofthe electrical device or detector 13 is a protective coil L having for waves which have the highiiequency of the waves to be received, an impedance much greater than the impedance of the device P, so that the coil will serve as a by-path for the currents due to the passage of the static charges in the elevated conductor V to earth. Such an Ainductance coil, which, as before stated, has an impedance for the high-frequency oscillations created in the elevated conductor by the waves tobe received, which is very'high compared to the impedance of the device4 P, operates practically as an open circuit for such oscillations, while aifordinga ready path to earth for the electrical charges which, 1n its" absence, vwould accumulate upon the elevated conductor andproduce dlsruptlve discharges to earth, thereby operating the oscillation detector. f

In Fig. 2 isv shown practically the same simple system as in Fig. l with the addition of acondenser C6 serially connected in the 'elevated conductor. The capacity of this condenser is so large as not to impede appreciably the passage of the hi h-frequency oscillations of wireless telegrap y while operating pract1cally as an open circuit for the more slowly varying currents by which thel elevated conductor is lmaintained free of lstatic charges and whichV pass t'o earth by way Aof the protective inductance coil L, which as before stated, operates practically asan open circuit for said high-frequency oscillations. i v

In Fig. 3' I have shown a receiving system, in which the circuit C3 C5 L2 C2 is made resonant to the frequency of the waves'to erases be received, and in which the capacity of the condenser C5 is small compared to the capacity of the condenser C3. 'Ihe protect# ive coil L connected across the terminals of that portion of the elevated conductor which includes the condensers C3 and C4 voperates as a by-path around said condensers for the currents produced by the static charges,

while impeding the'passage to earth of the high-frequency oscillations created by the waves to be received. It .will be noted that this coil L does not assist in'tuning any .cir-

cuit in any of the systems disclosed in the difference existed between the terminals of.

the condenser to produce disruptive discharges to earth which would have the eect of creating false 'signals in the detector P.

It is, as set forth in my Letters Patent No. 'a 67 ,979, advantageous to employ an elevated conductor consisting of a pluralityof wires,

and I have discovered that under certain circumstances 1t 1s preferable toemploy a smaller number of wiresfor receiving than for transmitting. In Fig. 5 I have shown a receiving system, having the serially included condenser C1 shunted by the protective inductance coil L, and the transmitting system set forth in my Letters Patent No. 714,756 associated with amultiple wire transmitting elevated conductor. The switch 5 pivoted between the jaws 4 and connecting,

in the position shown, said jaws with the jaws 4', connects the transformer secondary I, with all the wires, c and 'v' of the multiple transmitting conductor V. Vhen the switch 5 is thrown over so as to connect the jaws 4 with the jaw 3', the receiving system is connected with a portion only of the-wires of the multiple elevated conductor. In the system shown in Fig. 5 the two outer wires v v are connected to the receiving systemrwhen the switch is thrown over'so as to connect the jaws 4, and 3', but obviously any given number i f said wires might bes'o connected to the eceiving system by said switch 5 when in'such position.

In Fig. 6 I have shown the same system I' as Fi'g. 5 provided with means operated by the sending device K for automatically connecting ay given number ofthe wires of the multiple elevated conductor V with the receiving system and for connecting all saidwires withthe transmitting system. In this ligure the key carries at one end one member W of the electrolytic receiver P, and in the 'normal position of said key the member W is in contact with its cooperating member, the wires -v 'a' of the elevated conductor are disconnected from the rest of the system, and the wires c 'v are connected` to the receiving system which is earthed at Vthe point E.

Upon the depression of the key, the stud 6 presses the spring 7 down upon thecontact o, t-hereby closing the contact]c. .and shortcircuiting the receiving system at the point v" between -thetermmals o, o of the receiving system and connectin the secondary I2 to earth E by way of sai spring 7. At thesame time, or-shortly before or shortly afterward, the member -W is se arated' from vthe member P, thereby rendering the 'receiver inoperative, land either before or after, or between sald operations, and at anyv timeprior` to the closure of the Contact c,

vthe circuit of the magnet I is closed by the closure of the Contact lo. The energization of the magnet I by the battery B eEects the closure of the Contact 7c by the attraction of the armature 2 which is connected with the conductors 'v' fu and thereby, before the closure of the contact c, automatically connects' all the wires ofthe elevated conductor V with the transmittingsystem.

I claim, 1. In a wireless telegraph receiving system, an elevated conductor system includ' a condenser, and protective means connecte across the terminals of said condenser and having,.for'the frequency of the waves to be the impedance of said condenser thatit 0perates practically as an open circuit for cillations of said frequency. A f

2. 'In a wireless telegraph receivin sys.-

a condenser, and a protectivev inductance 4connected across the terminals 'of said conwaves to be received, an impedanceso much `greater than the impedance of said con# denser that it operates practically as an open circuit for oscillations of said frequency.

3. 'In a wireless telegraph System, a transmitting system, a receiving system, an elenumber of said wireswith the receiving system and for connecting all said Vwires wlth the transmitting system.

tern, an elevated conductor system inc uding denser and having, for the'frequency'of the received, an impedance so much greater than 3 vated conductorcomprising a plurality of wires, and means for connecting a small 4. In a Wireless telegraph system', a transl l 

